Control system for air compressors



Jlvxfne5flv928. Y f

. w, s. H. HAMILTON CNTR'oLsYsTE'M FOR AIR coMPRssoRs Filed June 25, 1925v 11 vnl/11,1111 1 Patented .lune 5', 1928.

rmiTso STATES PATENT orifice.

WILLIAM e.

H. HAMILTON, OF SCHENECTADYY, YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. i v

CONTROL SYSTEM FOR AIR COMPRESSORS.

' Application filed June 23,

lviy invention relates to control systems tor air compressors and particularly to control systems for air compressors used on locomotives` and the like which are adapted to be used with cars 'equipped either with air or vacuum brakes. l

it is customary to provide such locomotives with air compressors tor supplying the air brake system with air 'pressure and exhausters for establishing the desired vacuum in the vacuum brake system.`

One object ot my invention is to provide an arrangement whereby a compressor rmaybe usedv to supply air pressure to the air brake system and may operate also as an exhauster to establish the desired vacuumr in the vacuum brake system. An advantage ot' such an arrangement is that ihrer-luces the number of dilierent kinds ot' apparatus required on the locomotive.

' Another object ot' my invention is to provide a control arrangen'ient in a combined air and vacuum brake system whereby iinder certain conditions the vacuui'n in the vacuum brake system. is maintained by anv exliauster and the air pressure in the air brake system is maintained within certain limits by an air compressor and whereby under certain other conditions the connections ot the air `compressor are changed so that it operates as an exhaustei to aid in establishing the vacuum in the vacuum brake system.

Another-object of my invention is to provide a control arrangement for two air compressors ona locomotive whereby both conipressoi's operate together to maintain the air pressure in the air brake system within predetermined limits when the locomotive is being used with a train equipped with air brakes7 and whereby one of the compressors operates as an exhauster the otliercoinpressor operates asa compressor except under certain conditions oi the vacuum brake system, when the locomotive is used with a train equippediwith vacuum brakes.

My invention will be betterunderstood trom the following description, taken. in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing which shows diagraniniatically a portion of a combined air and vacuum brake system fora locomotive embodying my invention, 1 and 2 rep- 1926. seriai No. 118,092.

resent the air and vacuum reservoirs respec# air y,brakes on a ytrain which is equipped with air brakes and the brake valve 6- is connected by various pipes, not shown,` vwhereby the engineer can control the vacuum brakes on a train which is' equipped with vacuum brakes. Since-my invention does not re late to any particular type of air or vacuum brake-system or combination of the two7 and such' systems are old and well known in the art, I have deemed it desirable toshowr only such a portion of the two brake systems as will enable one to understand the .present invention.

The air reservoir l is adapted to be supplied with air pressure from three motor driven air compressors 8, 9 and 10, which may be of any suitable type. examples of which are well known in the art. The ci'icuit 4of the motor 'l1 drivinglthe compressor 8 is arranged to be completed byr means of a suitable pressure operated switch 12, eX amples of which are well known in the art, when the pressure in the air reservoir 1 decreases below a predetermined value and to be openedby the switch 12 when the reservoir pressure is above a predetermined value.

The circuits of motors 13 and 14 of the air compressors 9 and 10, respectively, vare controlled by a similar pressure'op'erated vswitch 15 so that they are completed when the pressure in the niainreservoir 1 isbelow a predetermined value and are opened when the pressure' is restored to a predetermined value. The compressor 11 is ,smallery than the other two compressors and the pressure switch 1Q is set 'to operate at lower Values ot' pressure than the pressure switch 15 so that'the compressor 11 is in operation only under certain conditions, as

' will be pointed out more fully hereinat'teip In order that the compressors 9 and 10 may .also be used as exhausters t'o maintain the desired vacuum in thevacuum lreservoir 2 when the locomotive is used with a train y. magnet valve which, when its magnet which is equipped with vacuum brakes, l provide each oi"- these two con'ipressors with a transiter' valve 16 whereby the connections oi? the inlet and outlet pipes oi the respective compressors are changed sothat instead of ,taking air from `the atmosphere, compressing it and discharging; it intoan air reservoir, the compressor takes air trom the vacuum reservoir, compresses. it,- and discharges it into the atmosphere. Therefore lwhen the connections are changed in this manner the compressors operateas exhausers for the vacuum brake system.

Each transfer valve 16 comprises a slide valve 17 which is provided with ports 18 and 19. Each valve is so' arranged that when it is in the position shown in the drawing, the port 19 connect-s inlet pipe 20 oi its compressor to atmosphere and the outlet pipe 21 is uncovered so that it' com* municates with the air reservoir 1. Each slide valve 17' is normally biased to the position Ashown in the drawingl by a spring 22 so that it there is no air pressure lthe valve moves to the compressor position. Attached to each slide valve are two pistons andai.y which are arranged in suit-able piston chambers. is a magnet valve which, when its magnet 26 is deenergized, establishes con'r inunication between the right hand side ot piston 2d and atmosphere and which, when its magnet 26 is energized, establishes communication between the right hand side ot piston 24 and the lair reservoir 1. 27' is a 28 is deenergrized, establishes communication between the leit hand sideoit piston 23 and the air reservoir 1 and which, when its magnet 28 is energized, establishes communication between the lett hand side ot' the piston and atmosphere. 1t will be observed there tore that when both of the magnets 26 and 28 are deenerggized, air pressure will aid the spring 22 in maintaininp,` the valve 12' in the lposition shown and that whenboth `oit the magnets Q6 and 28 are simultaneously energized air pressure is admitted 'to the right hand side of piston 2st and exhausted trom the lett hand side of piston 23 so that slide valve 17 is moved to the lett.` In its lett position the port 18 of the valve connects outlet pipe 21 ot the associated compressor to atmosphere and connects the inlet pipe 2O thereotl to the vacuum reservoir so that the associated compressor acts as an exhauster tor the vacuum brake system. 'llhereiford when the magnets 26 and 28 ot any transler valve are deenergized, the associated compressonfwhen in operatirm` supplies ai r pressure to the Vair reservoir 1 and when the associated magnets 26 and 28 are energized the compressor exhausts air from the vacuum reservoir 2..

ln order to control the operation ot the 'compressors 9 and 10 in accordance with the type of brakes on 'the train with which the locomotive is used, a manually controlled switch 30 is provided for controlling` the circuits of the compressor motors 13 and 14 and the magnets' 26 and 28 ot the transfer valves 17. lillhen the locomotive is used with a train equippedv with air brakes, the control switch 30 is placed in its upper position shown, in which position the circuits ot 'the magnets 26 and 2S are open so that both oi" the compressors 9 'and 10 operate `to supply air to the air reservoir 1.

ldlhen the locomotive is used with a train equipped with vacuum brakes, the control switch 30 is moved to its lower position, in

which position it completes the circuits ot the contactor 34., which completesthe circuit ot compressor motor 13 across the trolley crcuit 35, and the circuits otl the magnets 26 and 28 oi the transfer valve 16 associated with compressor 9 so that the compressor operates continuously as an exhauster to exhaust air trom the vacuum reservoir 2. The contact-or 36, which completes the circuit ot' the compressor motor 1dacross the trolley circuit 35, is still under the control ot the pressure switch 15 so that the compressor 10 operates to maintain the desired pressure in tl e air reservoir 1, since the locomotive is usually provided with air brakes and therefore it is necessary to maintain air pressure in the reservoir 1.

Since in vacuum brake systems the brakes are applied by breaking` the vacuum and the brakes are released by restoring the vacuum, it is desirable to have the evacuating` means arrangedso that it quickly establishes the desired vacuum in order that a quick release ot the brakes may be eitected. Therefore, l provide an arrangement whereby the compressor 10 is made to operate as an exhauster to aid the compressor 9 in restoring,` the vacuum in the vacuum reservoir 2 when the vacu-V um brakes are being,` released. For accomplishinrol this result l provide the vacuum brake valve 6 with a suitable control switch 37 which is arranged so that it is closed when the brake valve is in its release posi.- tion. Such brake valves, with auxiliary con trol switches which are closed incertain positions ot the valve are old and 'well known in the art. When the switch rWis closed, the circuits ot' the magnets :26 and .28ct the transfer valve 16 associated Vwith the compressor 10 are circuit o t the contacter thatL the compressor 1() hauster.

l? or supplying the various electroresponsive control. devices with suitable current` I provide a motor generator set il), the motor 41 oi" which is arranged to be connected ari-css the 'trolley lby a suitable switch 42. fairy other suitable source of control cur rent, however, may be used. F or maintain-v 36 is completed, so operates asran eX* completed and thenum reservoir, two pistons attached to said valve, and means for establishing,` communication between one side oit one of said pistons and atmosphere and between the opposite side oi" the other of said pistons and said air reservoir to effect the movement of said Valve from one ot said positions to the other'. y

6. In con'ibination1 an air reservoir, a Vacn uam reservoir7 a compressor, a pneumatically operated transfer Valve arranged in one position to establish a connection between said air reservoir and said compressor whereby said compressor snppliesair under pressure to said air reservoir and in another position to establish a connection between said Vacuum reservoir and said compressor whereby said compressor exhausts air trom saidv Vacuum reservoir7 two pistons attached to said Valve, and means 'ifor establishing` communi cation between one side oi one ot said pistons and atmosphere and between the opposite side of the other ot said 'pistons and said air reservoir to eltect the movement of said valve from onefot said positions to the other and for establishing connnnnicatien between said one side of said one of said pistons and said air reservoir and between the said op posite side ot the said other oi"l said pistons and atmosphere to eect the movement ot Said valve 'trom said other positinn to said one of said positions.

7. ln a combined air and Vacuum brake system, a vacuum brake valvelor controlling the operation ot the brakes, a compressor, a vacuum reservoir7 an airreservon, means for connecting' said Compressor so that it operates as an exhauster to maintain a Vacnnm in said Vacuum reservoir, second compressor normally arranged to maintain the pressure in said air reservoir within predetermined limits, and means controlled by said Vacuum brake Valve `for effecting a change in the connections oi said second compresser so that it operates as an exhauster il'or said Vacuum reservoir. y 4

S. in a combined air and vacuum brake system, a vacnnn'i brake Valve for controlling the operation oit the brakes, a compressor, a vacuum reservoiran air reservoir, means for connecting said compressor so that it oliierates Yas an exhauster to maintain a Vacuum in said vacuum reservoir, a second compri or normally arranged to maintain the pressure in said air reservoir Within predeteiin'iined lir its7 and a transfer Valve controiled by said Vacuum brake Valve Vtor effecting` a change in the connections of saidsecond comijnessor when said brake valve is in a pesition to release the Vacuum brakes so that said ond compressor .operates as an eX- hans presser in restoring` the vacuum in said Vacnnni reservoir. y

Q.' in a combined air and vacuum brake teni, a vacuum brake valve for controlling the operation oi the brakes7 a compres sor,l a vacuum reservoir, an air reservoir, inerme 'tor connecting said compressor so that it' operates as an exhauster to maintain a 'Vacuum in said Vacuum reservoir, a second ssor normally arranged to maintain re in said air reservoir within prede@ :mined limits, a transfer Valve controlled by said bralze valve for effecting( a change in the connections of said second compressor when said brake Valve is in a position to rethe Vacuum brakes vso that said second eonipressor operates as an eXha-nster to assist said iirst mentionedcompressor in restoring tric vacinnn in said vacuum reservoir, and a third compressor arranged to maintain the pi ".:re in said air reservoir within predetermined limits while said second compressor operating as an eXhauster. i

In witness whereof, have hereunto set my hand this 22nd day oi June, 1926.

VILLTAM S. H. ll-LMLTOIT.

rto assist said tirst mentioned com- 

